Golf club shaft

ABSTRACT

A golf club shaft having an exterior with a non-circular cross-section along at least a portion of its length is disclosed. In one embodiment, the cross-section of the exterior of the shaft along an intermediate portion of the shaft between the butt end and the tip end is non-circular. In this embodiment, the cross-section of the exterior of the shaft at the end regions containing the butt and tip ends of the shaft may be circular. The cross-section of the intermediate portion may be any suitable shape, such as a symmetrical shape. In one version of such an embodiment, the cross-section of the exterior of the shaft along an intermediate portion of the shaft is substantially triangular in configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/324,067, filed Dec. 30, 2005 (pending).

FIELD OF THE INVENTION

This invention relates to golf clubs, more particularly to golf clubshafts. More particularly still, this invention relates to golf clubshafts having a non-circular exterior cross-section along at least aportion of their length.

BACKGROUND OF THE INVENTION

Currently, golf club shafts are hollow steel or graphite tubes that havea relatively thick outside dimension at the grip end of the golf club,that narrows as the club head is approached. Some golf club shafts,particularly those made of steel, may have a series of steps therein. Inthese shafts, the thickness of the shafts changes to a narrowerthickness at each step from the grip end to the tip end. Other golf clubshafts taper smoothly from the grip end to the tip end. Still other golfclub shafts, such as the TAYLOR MADE® Bubble™ shaft described in U.S.Pat. No. 5,316,299 issued to Feche, et al. on May 31, 1994, have haddiscontinuities in thickness, such as a bubble, between their butt endand tip end.

Golf club shafts must meet the requirements of the United States GolfAssociation Rules of Golf (“Rules of Golf”) to be considered “legal” fortournament play. The USGA Rules require in Appendix II, Rule 4-1b, thatthe shaft be so designed and manufactured that at any point along itslength:

-   -   (i) it bends in such a way that the deflection is the same        regardless of how the shaft is rotated about its longitudinal        axis; and    -   (ii) it twists the same amount in both directions.

This Rule is believed to be the reason that most golf club shafts arecurrently of circular cross-section. Over the years, golf club shaftshave been proposed with various other cross-sections. One example ofsuch a shaft is described in U.S. Pat. No. 5,545,094 issued to Hsu. Mostof these proposed shafts are not believed to have been marketed on acommercial scale in the U.S. One possible reason for this may be thatthey have not received U.S.G.A. approval. Whether the shaft described inthe Hsu reference has been approved, however, is not known.

SUMMARY OF THE INVENTION

The present invention relates to golf club shafts having an exteriorwith a non-circular cross-section along at least a portion of the lengthof the shaft.

There are numerous, non-limiting embodiments of the invention. Allembodiments, even if they are only described as being “embodiments” ofthe invention, are intended to be non-limiting (that is, there may beother embodiments in addition to these), unless they are expresslydescribed as limiting the scope of the invention.

The golf club shaft has a longitudinal axis, a cross-section, a buttend, a tip end, and a length extending from the butt end to the tip end.In one non-limiting embodiment, the cross-section of the exterior of theshaft along an intermediate portion of the shaft between the butt endand the tip end is non-circular. In this embodiment, the cross-sectionof the exterior of the shaft at the end regions containing the butt andtip ends of the shaft may be circular. The cross-section of theintermediate portion may be any symmetrical shape. In one version ofsuch an embodiment, the cross-section of the exterior of the shaft alongan intermediate portion of the shaft is substantially triangular inconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed theinvention will be better understood from the following description takenin conjunction with the accompanying drawings (some of which have beenenlarged).

FIG. 1 is a perspective view of a golf club comprising one embodiment ofthe golf club shaft of the present invention.

FIG. 2 is one possible end view of the golf club shaft at the butt endof the shaft.

FIG. 3 is one possible end view of the golf club shaft at the tip end ofthe shaft.

FIG. 4 is one possible cross-sectional view of the golf club shaft takenalong line 4-4 of FIG. 1.

FIG. 5 is a cross-sectional view of another embodiment of the golf clubshaft taken along line 4-4 of FIG. 1.

FIG. 6 is a cross-sectional view of another embodiment of the golf clubshaft taken along line 4-4 of FIG. 1.

FIG. 7 is a partially fragmented, enlarged perspective view of oneembodiment of the golf club shaft of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of a golf club 20 that is provided with onenon-limiting embodiment of the golf club shaft of the present invention.

The golf club 20 has a shaft 22, a grip 24, and a club head 26. Theshaft 22 runs from the grip end (“upper end”) 20A of the club to theclub head end (“lower end”) 20B. The end of the shaft 22 at the upperend 20A of the club is referred to as the “butt” 22A of the shaft. Theend of the shaft 22 at the lower end 20B of the club is referred to asthe “tip” 22B of the shaft. The club head 26 has a club face 28 forstriking the ball, a back 30 on the opposite side of the club head, asole 31, and a hosel 32 (which may be optional) where the tip 22B of theshaft 22 is inserted into the club head 26. The golf club shaft 22 has aleading edge 34 that is on the half of the shaft aligned with the face28 of the golf club. The shaft 22 has a trailing edge 36 on the half ofthe shaft aligned with the back of the club head 30.

The golf club shaft 22 may be of any suitable length. Typical lengths ofshafts range from about 40-41 inches (about 100-105 cm) for shaftsdesigned to be installed in “iron” type golf clubs to about 46 inches(about 115-120 cm), or more, for shafts designed to be installed in“wood” type golf clubs.

The golf club shaft 22, along its length, comprises a first end portion(or first end region) 38 comprising the butt end 22A of the shaft, asecond end portion (or second end region) 42 comprising the tip end 22Bof the shaft, and an intermediate portion (or intermediate region) 40between said first and second end portions 38 and 42. These threeportions of the shaft 22 may be any suitable length. That is, they maycomprise any suitable portion of the overall length of the shaft. Thedifferent portions of the shaft 22 may each comprise any suitablepercentage of the overall length of the shaft including, but not limitedto about: 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%,90%, or 95%, or any range extending from one of these percentages toanother of these percentages. For example, in one embodiment, the threeportions of the shaft 22 may each comprise about ⅓ the overall length ofthe shaft 22. In other embodiments, one portion of the shaft 22 maycomprise less than or equal to about ¼ the overall length of the shaft22, and the two remaining portions may comprise the remaining ¾ of thelength of the shaft (e.g., one of the remaining portions could compriseabout ¼ of the overall length of the shaft 22, and the other portionremaining could comprise about ½ the overall length of the shaft 22).Other relationships between the lengths of the different portions of theshaft 22 are also possible.

The first end portion 38 of the shaft 22 may, for example, extenddownward from the butt end 22A of the shaft any suitable distance towardthe tip 22B of the shaft. In one embodiment, the first end portion 38may extend downward to the place where the shaft 22 emerges from thegrip 24. Golf club grips 24 are typically about 10-11 inches (about25-28 cm) long. In other embodiments, the first end portion 38 mayextend downward beyond the location where the shaft 22 emerges from thegrip 24. It should be understood that the brackets designating the threeregions of the shaft are for convenience only, and represent just onepossible embodiment, and the three portions of the shaft 22 are notlimited to the exact dimensions delineated by the brackets in FIG. 1.

The intermediate portion 40 may, for example, extend from the locationwhere the grip 24 begins (the lowermost portion of the grip 24) to thelocation where the shaft 22 is inserted into the hosel 32 or the clubhead 26. This region of the shaft may be referred to herein as the“exposed portion” of the shaft 22. In other embodiments, as shown, forexample, by the inner set of brackets 40′ in FIG. 1, the intermediateportion may comprise less of the overall length of the shaft than theexposed portion of the shaft. When the intermediate portion 40 of theshaft comprises less of the overall length of the exposed portion of theshaft, it may comprise any suitable percentage of the overall length ofthe exposed portion of the shaft including, but not limited to about:2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or95%, or any range extending from one of these percentages to another ofthese percentages. In still other embodiments, the intermediate portion40 of the shaft 22 may comprise a larger portion of the shaft 22 thanthe exposed portion of the shaft 22. In these latter embodiments, someof the intermediate portion 40 of the shaft may lie underneath the grip24 and/or within the hosel 32 or club head 26.

The intermediate portion 40 of the shaft may be centered relative toeither the overall length of the shaft, or relative to the exposedportion of the shaft 22. In other embodiments, however, the intermediateportion 40 of the shaft 22 need not be centered in such a manner. Theintermediate portion 40 of the shaft 22 may, for instance, be locatedcloser to the butt 22A, or alternatively, closer to the tip 22B of theshaft 22. The shaft 22 has a mid-point, M, along its length between thebutt 22A and tip 22B. The intermediate portion 40 of the shaft may belocated entirely above the midpoint of the shaft 22, or entirely belowthe midpoint of the shaft 22. In other embodiments, a portion of theintermediate portion 40 of the shaft 22 may be located above themidpoint, M, of the shaft, and a portion of the intermediate portion 40of the shaft 22 may be located below the midpoint, M, of the shaft. Insome embodiments, the intermediate portion 40 of the shaft may either belocated substantially above the midpoint, M, of the shaft 22, orsubstantially below the midpoint, M, of the shaft 22. In someembodiments, the intermediate portion 40 of the shaft 22 may be locatedwithin the upper ⅓ of the shaft, the lower ⅓ of the shaft, or the middle⅓ of the shaft.

The second end portion 42 of the shaft 22 may, for example, extendupward from the tip 22B of the shaft any suitable distance toward thebutt end 22A of the shaft. In one embodiment, the second end portion 42may extend upward from the tip 22B of the shaft to the uppermost portionof the hosel 32. In other embodiments, the second end portion 42 mayextend upward beyond the uppermost portion of the hosel 32 (or to theplace where the shaft emerges from the club head 26, if there is nohosel 32).

The different portions of the shaft 22 may have any suitablecross-sectional configuration. As shown in FIG. 2, in the embodimentshown in FIGS. 1-5, the cross-section of the exterior of the shaft 22along at least a portion of the length of the first end portion 38 ofthe shaft 22 (containing the butt 22A of the shaft) may be circular.This allows the shaft 22 to fit inside conventional grips 24. The crosssection of the grip 24 must be circular to conform to USGA Rules. Asshown in FIG. 3, in this embodiment, the cross-section of the exteriorof the shaft 22 along at least a portion of the length of the second endportion 42 of the shaft 22 (containing the tip 22B of the shaft) mayalso be circular. This allows the tip end 22B of the shaft 22 to fitinto conventional club head hosels 32, or other openings in the clubhead for receiving a shaft.

The cross-section of the exterior of the shaft 22 in one or both of thefirst end portion 38 and second end portion 42 may be circular along anysuitable portion of the length of such portions, including the entirelength of such portions, or substantially the entire length of suchportions. However, it should be understood that it is within the scopeof the present invention for one or more sections along the length ofthe first end portion 38 or second end portion 42 to have across-section that is non-circular.

In this embodiment, however, as shown in FIG. 4, the cross-section ofthe exterior of the shaft 22 along at least a portion of the length ofthe intermediate portion 40 of the shaft 22 is non-circular. Thecross-section of the exterior of the shaft 22 in the intermediateportion 40 may be non-circular along any suitable portion of the lengthof the intermediate portion 40, including the entire length of theintermediate portion 40, or substantially the entire length of theintermediate portion 40. It should be understood, however, that it iswithin the scope of the present invention for one or more sections alongthe length of the intermediate portion 40 to have a cross-section thatis circular. In the embodiment shown in FIG. 4, the shaft 22 issubstantially hollow. As shown in FIG. 4, the shaft 22 has an interiorsurface 44 and an exterior surface 46.

The exterior surface 46 of the intermediate portion 40 may have anysuitable non-circular cross-sectional shape along at least a portion ofthe length thereof. Suitable shapes include symmetrical shapes. The golfclub shaft 22 may, for example, have an intermediate portion 40 with anexterior 46 cross-sectional configuration of a regular polygon, or amodified regular polygon shape. In certain embodiments, the exteriorconfiguration of the intermediate portion 40 of the shaft 22 may besubstantially, or entirely: a triangular, square, pentagonal, hexagonal,septagonal, octagonal, or other polygon with any other number of sides).In other embodiments, the exterior configuration of the shaft 22 may notinclude configurations in which the cross-sectional configuration is oneor more of the foregoing shapes. In the particular embodiment shown, thecross-section of the exterior 46 of the shaft 22 along the intermediateportion 40 of the shaft 22 is substantially triangular in configuration.

The portion of the golf club shaft 22 at this particular cross-sectionhas an exterior cross-section that is substantially in the configurationof an equilateral triangle. The cross-section of the shaft has threesides 48, and three corners 50. The cross-section of the shaft 22 shownin FIG. 4 is symmetrical about the longitudinal axis, L. A shaft havingthe cross-section of a regular polygon (all sides being substantiallythe same length) is believed to have the same bending propertiesregardless of how the shaft is rotated about its longitudinal axis, L,even when the shaft 22 is bent at locations corresponding to the corners50.

The substantially triangular shape of the cross-section of the shaft 22may be exactly in the shape of a triangle, with straight side edges 48.However, in the embodiment shown, the cross-section is in a modifiedtriangular-shaped configuration. In the embodiment shown in FIG. 4, thesides 48 of the modified triangular-shaped cross-section are convexoutwardly curved, and the corners 50 of the modified triangular-shapedcross-section are rounded. The cross-section of the shaft 22 can, thus,be formed by rectilinear segments, curvilinear segments, or both. Theother polygon-shaped structures described herein can also be similarlymodified. In other embodiments, the sides and/or the corners of thepolygon can have larger or smaller radii of curvature than that shown inthe drawings. In still other embodiments, the sides of the polygon (oreven the corners thereof), instead of being convexly curved, may beconcavely curved.

The cross-section of the interior surface 44 of the intermediate portion40 of the shaft 22 can be circular as shown in FIG. 4. In otherembodiments, however, as shown in FIG. 5, the cross-section of theinterior surface 44 of the intermediate portion 40 of the shaft 22 canhave a non-circular configuration. For instance, as shown in FIG. 5, thecross-section of the interior surface 44 of the intermediate portion 40of the shaft 22 has a similar configuration to the cross-section of theexterior surface 46 of the shaft. Thus, in the embodiment shown in FIG.5, both the interior surface 44 and exterior surface 46 of theintermediate portion 40 of the shaft 22 may have a substantiallytriangular configuration.

The shaft 22 has side walls 52 between the interior and exteriorsurfaces 44 and 46. The side walls 52 can be uniform, or non-uniform inwidth, or thickness, around the cross-section of the shaft. For example,the side walls 52 may be substantially uniform in thickness in theembodiment shown in FIG. 5 where both the interior surface 44 andexterior surface 46 of the intermediate portion 40 of the shaft 22 havea substantially triangular configuration. The side walls 52 of theintermediate portion of the shaft 22 may have a non-uniform thickness inembodiments such as the one shown in FIG. 4 where the cross-section ofthe interior surface 44 of the intermediate portion 40 of the shaft 22is circular.

FIG. 6 shows an alternative embodiment in which the shaft 22 comprises atwo component structure. In the two component structure shown in FIG. 6,the shaft 22 comprises an inner component 54, such as a component havinga circular cross-section, and an outer component 56 having an exteriorsurface that provides the shaft with the desired non-circularcross-section. In one version of such a two component structure, theinner component 54 may comprise a shaft having a circular cross-section.The inner shaft component 54 in some embodiments, may be made of steel,graphite, or some other suitable material, and the outer component 56may be a flexible material joined thereto.

The term “joined”, as used herein, encompasses configurations in whichan element is directly secured to another element by affixing theelement directly to the other element; configurations in which theelement is indirectly secured to the other element by affixing theelement to intermediate member(s) which in turn are affixed to the otherelement; and configurations in which one element is integral withanother element, i.e., one element is essentially part of the otherelement. The term “joined” includes both those configurations in whichan element is temporarily joined to another element, or in which anelement is permanently joined to another element.

In the two component structure shown in FIG. 6, the inner component 54has an inner surface and an outer surface, and both the inner surfaceand the outer surface have a circular cross-section. In addition tobeing flexible, the outer component 56 may also be compressible and/orresilient. In still other embodiments, however, the outer component 56need not be compressible or resilient. This two component structure canform any suitable portion(s) of the shaft 22, including one or both ofthe end portions 38 and 42 of the shaft 22, or the intermediate portion40 of the shaft 22.

In other embodiments, as shown in FIGS. 2-5, it may be desirable for theshaft 22 to comprise a single component structure in which there are noseparate inner and outer components. This may be desirable for anysuitable reason. Such a structure may, for instance, be desirable: froma manufacturing standpoint (that is, to simplify manufacturing); tofacilitate U.S.G.A. approval; or, for any other purpose.

The different portions of the shaft 22 (first end portion 38,intermediate portion 40, and second end portion 42) can have anysuitable interior dimensions. It is, therefore, not necessary for theinterior dimensions of the different portions of the shaft 22 (first endportion 38, intermediate portion 40, and second end portion 42) to beequal since shafts typically taper from a larger exterior dimension to asmaller dimension from the butt 22A of the shaft to the tip 22B of theshaft 22. Thus, it may be desirable for the interior dimension (or the“inside diameter” for a cylindrical portion) of the shaft 22 to besmaller at the tip 22B than at the butt 22A of the shaft 22. Inaddition, it may be desirable for the thickness of the walls 52 of theshaft 22 to be larger at the tip 22B than at the butt 22A of the shaft,particularly in the case of shafts made of graphite. This may be done toprovide the shaft with greater strength at the tip 22B end.

The different portions of the shaft 22 (first end portion 38,intermediate portion 40, and second end portion 42) can have anysuitable exterior dimensions. It is desirable for the first end portion38 of the shaft 22 to have an exterior configuration and dimensions thatmake it is capable of fitting into a conventional grip 24. Examples ofsuitable exterior dimensions for the butt 22A of the shaft 22 include anoutside diameter (or “OD”) of about 0.6 inches, 0.625 inches, 0.63inches, and 0.635 inches (about 1.5 cm, 1.59 cm, 1.6 cm, and 1.61 cm).It is desirable for the second end portion 42 of the shaft 22 to have anexterior configuration and dimensions that make it is capable of fittinginto the hosel 32, or other opening in a club head 26 for receiving ashaft. Examples of suitable exterior dimensions for the tip 22B of theshaft include an outside diameter of about: 0.335 inches, 0.35 inches,and 0.37 inches (about 0.85 cm, 0.9 cm, and 0.94 cm). The exteriordimensions of the shaft 22 may generally decrease within any one or moreportions of the shaft 22 from the butt 22A of the shaft to the tip 22Bof the shaft 22.

The exterior dimensions of the intermediate portion 40 of the shaft 22may be of a size that is between the exterior dimensions of the firstend portion 38 and second end portion 42 of the shaft 22. However, theexterior dimensions of the intermediate portion 40 of the shaft 22 arenot limited to those that are of a size that is between the exteriordimensions of the first end portion 38 and second end portion 42 of theshaft 22. For example, it is possible for one or more portions of theintermediate portion 40 of the shaft 22 to be larger than the exteriordimension of a portion of the first end portion 38 of the shaft. It ispossible for one or more portions of the intermediate portion 40 of theshaft 22 to be smaller than the exterior dimension of a portion of thesecond end portion 42 of the shaft. The shaft 22 may, or may not, beconstructed so that any variations in the cross section of the shaft 22are gradual so that there is a smooth transition along the shaft betweensuch different cross-sections. In addition, the shaft 22 can be providedwith a series of tapering steps similar to ones found in conventionalcylindrical steel golf club shafts.

There are also transition portions (or “transition regions”) 58 and 60between the different portions of the shaft 22 where the exterior shapeof the shaft changes from one cross-sectional shape to a differentcross-sectional shape. FIG. 7 shows one non-limiting embodiment of ashaft with transition regions 58 and 60. (The interior of the shaft 22is shown in dashed lines in FIG. 7 because it can have any suitableconfiguration.) As shown in FIG. 7, the first transition portion (or“first transition region”) 58 is at the location where the circularconfiguration of the first end portion 38 of the shaft 22 changes to thesubstantially triangular configuration of the intermediate portion 40.The second transition portion (or “second transition region”) 60 is atthe location where a substantially triangular configuration of theintermediate portion 40 of the shaft 22 changes to the circularcross-sectional configuration of the second end portion 42. Thesetransition portions may be considered to comprise portions of the shaft22 that are separate from the first end portion 38, intermediate portion40, and second end portion 42, or they may be considered to comprisepart of the three main portions of the shaft 22. The transition portionsmay also be considered to comprise portions of the shaft where oneportion of the shaft merges into another portion of the shaft 22.

The transition portions 58 and 60 can have any suitable configuration.In the case of the embodiment shown in the drawings which has anintermediate portion 40 with a substantially triangular cross-section,the first transition portion 58 comprises a portion of the shaft 22 inwhich the cross-section has a radius of curvature that decreases atthree locations (or “places”) 62 disposed on the exterior surface 46 ofthe shaft 22 from the first end portion 38 toward the intermediateportion 40. These three locations 62 are disposed approximately equaldistances from each other around the perimeter of the exterior surface46 of the shaft 22. If the cross-section of the shaft is looked at ingeometric terms, these three locations may be disposed radially outwardfrom the longitudinal axis, L, of the shaft at points that areapproximately 120° apart around the perimeter of the exterior surface 46of the shaft 22. The portions 64 of the perimeter of the exteriorsurface 46 of the shaft 22 that lie between the aforementioned threelocations 62 have a radius of curvature that increases as the shaft 22transitions from the first end portion 38 to the intermediate portion40.

The second transition portion 60 comprises a portion of the shaft 22 inwhich the cross-section has a radius of curvature that increases atthree locations (or “places”) 66 disposed on the exterior surface 46 ofthe shaft 22 from the intermediate portion 40 toward the second endportion 42. These three locations 66 are disposed approximately equaldistances from each other around the perimeter of the exterior surface46 of the shaft 22. These three locations 66 may be disposed radiallyoutward from the longitudinal axis, L, of the shaft at points that areapproximately 120° apart around the perimeter of the exterior surface 46of the shaft 22. The portions 68 of the perimeter of the exteriorsurface 46 of the shaft 22 that lie between the aforementioned threelocations 66 have a radius of curvature that decreases as the shaft 22transitions from the intermediate portion 40 to the second end portion42.

The transition portions 58 and 60 can be relatively smooth, or moresharp or abrupt. The transition portions 58 and 60 may have any suitablelength. Suitable lengths include, but are not limited to: less than orequal to about 0.5 inch, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, . . .(etc.) inches (about 1.3, 2.5, 5, 7.5, 10, 12.5, 15, 18, 20, 23, 25.4,28, 30, . . . cm). Typically, the longer transition portions will besmoother. For example, a relatively smooth transition portion may beconsidered to be one that has a length greater than or equal to aboutany of the following: 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, . . .(etc.) inches. A relatively abrupt transition portion may be consideredto be one that has a length of less than or equal to any of the aboveamounts. In some embodiments of the shaft 22, the first and secondtransition portions 58 and 60 may both either be relatively smooth, orrelatively abrupt. In other embodiments of the shaft 22, one of thetransition portions may be relatively smooth, and one may be relativelyabrupt, or at least more abrupt than the relatively smooth transitionportion.

The cross-section of the shaft 22 can be aligned in any suitableorientation in the club 20 to form the leading 34 and trailing edges 36of the shaft. In certain embodiments, it may be desirable for one of thecorners 50 of such a triangular, or modified-triangle structure (orother polygon-shaped structure) to be aligned to form the leading edge34 of the shaft 22. In other embodiments, it may be desirable for one ofthe sides 48 of such a triangular, or modified-triangle structure (orother polygon-shaped structure) to be aligned to form the leading edge34 of the shaft 22.

FIG. 4 shows that when one of the corners 50 is aligned to form theleading edge 34 of the shaft 22, there are several different ways thatthe corner 50 can be positioned, and still form the leading edge 34. Asshown in FIG. 4, there are at least three axes, A1, A2, and A3, whichcan represent a plane that divides the shaft 22 into a leading half anda trailing half, which may be oriented to permit the corner labeled withreference number 50 to form the leading edge 34 of the shaft.

For example, if the shaft 22 in FIG. 4 is oriented so that axis A1divides the shaft 22 into a leading half and a trailing half, the cornerlabeled with reference number 50 will form the leading edge 34 of theshaft. However, this corner 50 will be oriented on the bottom portion ofthe shaft when the club is viewed from the position shown in FIG. 1. Inembodiments in which the shaft 22 is oriented so that axis A3 dividesthe shaft 22 into a leading half and a trailing half, the corner labeledwith reference number 50 will form the leading edge 34 of the shaft.However, this corner 50 will be oriented on the top portion of the shaftwhen the club is viewed from the position shown in FIG. 1. Inembodiments in which the shaft 22 is oriented so that axis A2 dividesthe shaft 22 into a leading half and a trailing half, the corner labeledwith reference number 50 will form the leading edge 34 of the shaft.However, this corner 50 will be oriented midway between the top and thebottom portion of the shaft when the club is viewed from the positionshown in FIG. 1. The cross-sections of the intermediate portion 40 ofthe shaft 22 in FIGS. 3 and 5-6 may also be oriented in any of themanners specified.

The golf club shaft 22 can be made of any suitable material ormaterials. The golf club shaft 22 can be made of a single material, orit can be made of more than one material. Suitable materials include,but are not limited to steel, graphite, aluminum, titanium, fiberreinforced plastic, or any other material known in the art for makinggolf club shafts. The shaft 22 can also be made of composites orcombinations of any of these materials.

The shaft 22, or any portion thereof, may be made of one or more (oreven multiple) layers of the same or different material. For instance,the shaft 22 can be made of multiple layers of graphite that are formedinto a tube. In some embodiments, such multiple layers can be formedinto the shaft 22 so that discrete layers remain visible as a laminateor layered structure to the unaided eye (that is, macroscopically). Inother embodiments, the multiple layers may be formed or molded, byheating or other methods, into a composite structure in which thediscrete layers are not visible to the unaided eye after the shaft hasbeen formed.

In certain embodiments, it may be desirable for the materials comprisingthe shaft 22 to be elastic and/or compressible. However, in otherembodiments, it may be desirable for the materials comprising the shaft22 to be substantially non-elastic and/or substantially non-compressiblewhen the shaft is in its finished form. In some embodiments, it may bedesirable for the materials comprising the shaft to exclude viscoelasticfoam material.

The first end portion 38, intermediate portion 40, and second endportion 42 can be made from the same material(s), or differentmaterials. In the embodiments shown in FIGS. 1-5, the first end portion38, intermediate portion 40, and second end portion 42 are made from thesame material(s). These same materials may be in the form of a singlematerial or a composite structure when the shaft 22 is in its finishedform. In other embodiments, instead of comprising a single material or acomposite structure, one or more of the first end portion 38,intermediate portion 40, and second end portion 42 can comprise any ofthe other types of structures described herein. The shaft 22 cancomprise any possible combination of the various materials or structuresdescribed herein as any one or more of its first end portion 38,intermediate portion 40, and second end portion 42.

The different portions of the shaft, first end portion 38, intermediateportion 40, and second end portion 42, can be comprised of a singlecontinuous piece, or they can comprise two or more segments. If theshaft 22 comprises two or more segments, the segments can be joinedtogether generally end-to-end, or in a partially overlapping end-to-endconfiguration. An example of a partially overlapping end-to-endconfiguration would be a shaft comprising at least two segments wherethe end of one segment fits into the end of another segment.

Numerous other embodiments are possible. For example, in otherembodiments, the shaft 22 need only have two regions with differentcross-sections. For instance, the shaft 22 may only have a first endportion, and the intermediate portion can also comprise the second endportion and extend all the way to the tip 22B of the shaft 22. In otherembodiments, the shaft 22 may have more than three regions withdifferent cross-sections. In these, or other embodiments, the interiorof the shaft 22 may be non-hollow. That is, the interior of the shaft 22may be filled, at least partially, or entirely with some substance orstructure. The golf club and shaft can also be provided with any of thefeatures described in, or be constructed in accordance with thedisclosures of: U.S. Pat. No. 5,316,299 issued to Feche, et al.; U.S.Pat. No. 6,561,992 B2 issued to Bamber; and, U.S. Pat. D-505,986 Sissued to Bamber.

The golf club shaft 22 described herein can provide one or moreadvantages. It should be understood, however, that the golf club shaft22 is not required to provide any advantages unless they arespecifically set forth in any of the appended claims. In addition, itshould be understood that the benefits described herein are prophetic,and remain to be proven by testing. The cross-sectional shape of theintermediate portion 40 of the shaft may, for example, be used to reducedrag on the shaft, to bring the golfer's swing into impact on a certainswing path, or both. The cross-sectional shape of the intermediateportion 40 may serve to assist the golfer in moving the club into theimpact zone by squaring the clubface. The shaft 22 may allow the golfclub to be swung faster by the player with the same or less effort tocreate more power, and longer shots, straighter shots (that is, it mayminimize shot dispersion), or both. It is believed that the golf clubshaft will conform to the Rules of Golf. The golf club shaft 22 isbelieved to bend in such a way that the deflection is the sameregardless of how the shaft is rotated about its longitudinal axis; andtwist the same amount in both directions even though it has anintermediate portion with a non-circular cross-section.

The golf club shaft 22 can be made in any suitable manner. Methods ofmaking golf club shafts are well known. Any suitable method can bemodified to produce the golf club shaft described herein. Somenon-limiting embodiments of methods for making golf club shafts aredescribed in: U.S. Pat. Nos. 6,171,696 B1 and 6,273,830 B1 issued toTakemura, et al., and U.S. Pat. No. 6,857,972 B2 issued to Kumamoto.These methods, or other methods, can be modified by utilizing a mandrelhaving the configuration desired for the inner surface of the shaft, andforming the shaft around the mandrel by casting, molding, forging, orotherwise shaping the shaft material or materials. For example, in oneembodiment of a method of making the shaft, the shaft is formed in amold that is provided in the configuration of the exterior surface ofthe shaft. Other methods of providing a golf club shaft with anon-circular cross-section are described in U.S. Pat. No. 6,561,992 B2issued to Bamber.

The disclosures of all patents and publications mentioned throughoutthis patent application are hereby incorporated by reference herein. Itis expressly not admitted, however, that any of the documentsincorporated by reference herein teach or disclose the presentinvention. It is also expressly not admitted that any of thecommercially available materials or products described herein teach ordisclose the present invention.

It should be understood that every maximum numerical limitation giventhroughout this specification includes every lower numerical limitation,as if such lower numerical limitations were expressly written herein.Every minimum numerical limitation given throughout this specificationincludes every higher numerical limitation, as if such higher numericallimitations were expressly written herein. Every numerical range giventhroughout this specification includes every narrower numerical rangethat falls within such broader numerical range, as if such narrowernumerical ranges were all expressly written herein.

While particular embodiments of the subject invention have beendescribed, it will be obvious to those skilled in the art that variouschanges and modifications of the subject invention can be made withoutdeparting from the spirit and scope of the invention. In addition, whilethe present invention has been described in connection with certainspecific embodiments thereof, it is to be understood that this is by wayof illustration and not by way of limitation and the scope of theinvention is defined solely by the appended claims which should beconstrued as broadly as the prior art will permit.

1. A golf club shaft having a longitudinal axis, a cross-section, anexterior surface, a butt end, a tip end, a first end portion comprisingsaid butt end, a second end portion comprising said tip end, and anintermediate portion between said first and second end portions, and alength extending from said butt end to said tip end, wherein at leastpart of said intermediate portion of said shaft has an exterior surfacewith a cross-section that is substantially triangular in configuration,wherein said substantially triangular cross-section has a peripheryformed by three sides that meet at rounded corners, wherein each of saidthree sides has a substantially equal length, and the three sides areconvex outwardly continuously around said periphery, and at least partof the length of said shaft in said first end portion has an exteriorsurface with a cross-section that is circular.
 2. The golf club shaft ofclaim 1 wherein said three sides of said periphery of said substantiallytriangular cross-section have equal lengths.
 3. The golf club shaft ofclaim 1 having an interior surface along at least a portion of itslength, and being hollow inside at least a portion of said interiorsurface.
 4. The golf club shaft of claim 3 wherein the cross-section ofsaid portion of said interior surface is substantially circular.
 5. Thegolf club shaft of claim 4 wherein said substantially circularcross-section of said portion of interior surface comprises at leastpart of the length of said intermediate portion.
 6. The golf club shaftof claim 5 wherein the interior surface and exterior surface of theshaft, along said at least part of the length of said intermediateportion, define a wall therebetween, and the wall has portions withdifferent thicknesses.
 7. The golf club shaft of claim 6 wherein thewall is thicker in the regions of the corners than in the regionadjacent the sides.
 8. The golf club shaft of claim 3 comprising amacroscopically single layer structure.
 9. The golf club shaft of claim3 wherein said first end portion, said second end portion, and saidintermediate portion of said shaft comprise the same structure andmaterial.
 10. A golf club shaft according to claim 1 further comprisinga club head joined to the second end portion of said shaft and a gripjoined to the first end portion of said shaft to form a golf club.
 11. Agolf club shaft having a longitudinal axis, an exterior surface, across-section, a butt end, a tip end, and a length extending from saidbutt end to said tip end, said golf club shaft comprising: (a) a firstend portion comprising the butt end of the shaft wherein thecross-section of the exterior of said shaft along a portion of thelength of said shaft extending from said butt end part of the distancetoward said tip end is circular; (b) a second end portion comprising thetip end of the shaft, wherein the cross-section of the exterior of saidshaft along a portion of the length of said shaft extending from saidtip end part of the distance toward said butt end is circular; and (c)an intermediate portion between said first and second end portions,wherein the cross-section of the exterior surface of said shaft along atleast part of the length of said intermediate portion is substantiallytriangular in configuration, wherein the substantially triangularcross-section has a periphery formed by three sides that meet at roundedcorners, wherein each of said three sides has a substantially equallength, and said three sides are convex outwardly continuously aroundsaid periphery.
 12. The golf club shaft of claim 11 having an interiorsurface along at least a portion of its length, and being hollow insideat least a portion of said interior surface.
 13. The golf club shaft ofclaim 12 wherein the cross-section of said portion of said interiorsurface is substantially circular.
 14. The golf club shaft of claim 11wherein at least one of said first end portion and said second endportion merges into said intermediate portion in a transition region,wherein in said transition region the configuration of the exteriorsurface of said shaft changes from one configuration to a differentconfiguration over a portion of the length of said shaft.
 15. The golfclub shaft of claim 14 wherein the exterior cross-section of the firstend, second end, and intermediate portions of said shaft each have atleast one radius of curvature, and said transition region is locatedwhere said first end portion merges into said intermediate portion,wherein said transition region comprises: (i) a portion of the shaft inwhich the cross-section has a radius of curvature at three spaced apartlocations disposed on the exterior surface of the shaft, wherein theradius of curvature at said three locations decreases from the first endportion toward the intermediate portion; and (ii) three portions of theperimeter of the cross-section of exterior surface of the shaft that liebetween the aforementioned three locations, wherein said three portionsof the perimeter of the shaft have a radius of curvature that increasesas the shaft transitions from the first end portion to the intermediateportion.
 16. The golf club shaft of claim 14 wherein the exteriorcross-section of the first end, second end, and intermediate portions ofsaid shaft each have at least one radius of curvature, and saidtransition region is located where said intermediate portion merges intosaid second end portion, wherein said transition region comprises: (i) aportion of the shaft in which the cross-section has a radius ofcurvature at three spaced apart locations disposed on the exteriorsurface of the shaft, wherein the radius of curvature at said threelocations increases as the shaft transitions from the intermediateportion to the second end portion; and (ii) three portions of theperimeter of the cross-section of exterior surface of the shaft that liebetween the aforementioned three locations, wherein said three portionsof the perimeter of the shaft have a radius of curvature that decreasesas the shaft transitions from the intermediate portion to the second endportion.
 17. The golf club shaft of claim 11 wherein said shaft, at anypoint along its length: (i) bends in such a way that the deflection isthe same regardless of how the shaft is rotated about its longitudinalaxis; and (ii) twists the same amount in both directions.
 18. A golfclub shaft according to claim 11 further comprising a club head joinedto the second end portion of said shaft and a grip joined to the firstend portion of said shaft to form a golf club.
 19. A golf club shafthaving a longitudinal axis, a cross-section, an exterior surface, a buttend, a tip end, a first end portion comprising said butt end, a secondend portion comprising said tip end, and an intermediate portion betweensaid first and second end portions, and a length extending from saidbutt end to said tip end, wherein at least part of said intermediateportion of said shaft has an exterior surface with a cross-section thatis substantially triangular in configuration and has three convex sidesthat meet at rounded corners, wherein each of said three sides has asubstantially equal length, and each side has a radius of greater thanthe maximum dimension of the shaft at the cross-section, and at leastpart of the length of said shaft in said first end portion has anexterior surface with a cross-section that is circular.